Fan vanes with protective devices have been previously proposed in the art. Typically, the known arrangements are of a mechanical variety and include blunt edges, or edges having a softer material mechanically fixed to the leading edges of each of the vanes of the propeller. These arrangements are generally useful, but over time, the point at which the device is fixed to the vane becomes worn due to continuous centripetal forces or alternatively, such devices do not fit precisely and this results in undesirable noise. A further disadvantage to the mechanical systems is that they tend to add significant mass to the vanes of the propeller which, in turn, is translated to the motor. This may cause the motor to overheat and in situations where the motors are battery driven, such as would be the case with personal systems, the result is premature battery drain. In the existing arrangements, turbulence or localized eddies also pose problems.
Other arrangements that have been previously proposed include glue or mechanical fastening such as with rivets, etc. These methods are extremely labour intensive and further, are quite susceptible to wear and eventual failure. In the case of the adhesive connection, over time, moisture conditions may alter the bond of the guard to the vane of the propeller thus resulting in the guard being thrown from the leading edge of the vane. This obviously creates a hazardous situation.
In view of the limitations of the prior art, it is clear that there exists a need for an improved method of bonding a guard to a leading edge of a propeller which does not suffer the limitations associated with mechanical fixture, attachment or adhesive attachment. The present invention is directed to satisfying this need and provides an improved arrangement.